字典是另一种可变容器模型,且可存储任意类型对象.字典的每个键值对(key=>value)分隔.
用途:记录多个值,列表是索引对应值,而字典是key对应值,期中key对value有描述性功能.
d = {key1 : value1, key2 : value2}
类转换:
items=[(‘name‘,‘egon‘),(‘age‘,18),(‘gender‘,‘male‘)] d={} for item in items: d[item[0]]=item[1] d=dict(items) print(d) #输出结果 {‘name‘: ‘egon‘, ‘age‘: 18, ‘gender‘: ‘male‘}
常用操作+内置方法
1.按key存取值:可存可取
dic={‘name‘:‘egon‘,‘age‘:18}
print(dic[‘name‘])
dic[‘name‘]=‘EGON‘
dic[‘gender‘]=‘male‘
print(dic)
#输出结果
egon
{‘name‘: ‘EGON‘, ‘age‘: 18, ‘gender‘: ‘male‘}
2.长度len (按key的个数取值)
dic={‘name‘:‘egon‘,‘age‘:18}
print(dic)
print(len(dic))
#输出结果
{‘name‘: ‘egon‘, ‘age‘: 18}
2
3.成员运算in和not in :是以字典的key为准
dic={‘name‘:‘egon‘,‘age‘:18}
print(‘name‘ in dic)
print(‘egon‘ in dic)
#输出结果
True
False
4.删除
dic={‘name‘:‘egon‘,‘age‘:18}
del dic[‘name‘]
print(dic)
#输出结果
{‘age‘: 18}
dic={‘name‘:‘egon‘,‘age‘:18}
res=dic.pop(‘name‘)
print(dic)
print(res)
#输出结果
{‘age‘: 18}
egon #有返回值
res=dic.popitem() print(res) #输出结果 (‘age‘, 18)
5.键keys(), 值values() , 键值对items()
>>> dic={‘name‘:‘egon‘,‘age‘:18}
>>>
>>> dic.keys()
dict_keys([‘name‘, ‘age‘])
>>> dic.values()
dict_values([‘egon‘, 18])
>>> dic.items()
dict_items([(‘name‘, ‘egon‘), (‘age‘, 18)])
6.循环
dic={‘name‘:‘egon‘,‘age‘:18}
for k in dic:
print(k)
for k in dic.keys():
print(k)
for v in dic.values():
print(v)
for k,v in dic.items(): #k,v=(‘name‘, ‘egon‘)
print(k,v)
#输出结果
name
age
name
age
egon
18
name egon
age 18
原文：https://www.cnblogs.com/kp1995/p/10003276.html